The Port Authority of New York and New Jersey, which operates the airport, says the breach occurred in Terminal C around 10 a.m.

Receive the latest local updates in your inbox

A terminal at Newark Liberty International Airport was briefly shut down Sunday after officials discovered that a passenger had made it through a security checkpoint without being properly screened.

The Port Authority of New York and New Jersey, which operates the airport, says the breach occurred in Terminal C around 10 a.m., causing a lockdown there that lasted for about two hours. Operations at the airport's two other terminals were not affected.

The breach caused numerous flight delays and required the re-screening of all passengers in the terminal.

It wasn't immediately clear how the passenger was improperly screened or how Transportation Security Administration officials at the terminal learned of the problem.

Get the latest from NBC 4 New York anytime, anywhere. Follow us on Twitter, Facebook and Google+. Get our apps here and sign up for email newsletters here. Get breaking news delivered right to your phone -- just text NYBREAKING to 639710. For more info, text HELP. To end, text STOP. Message and data rates may apply.